VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 solution found, about voltage Drain

I have installed a new 6 volt battery... rebuilt generator and new wiring harness..... new ignition switch... an new heavy duty battery disconnect switch and new large (finger thick positive & negative cables) ( the switch is on the ground cable)
I have a solar powered 6 volt battery charger hooked up to maintain the battery.. when sitting....
OK the Question.... when my heavy duty battery disconnect switch is turned OFF..... the battery reads ... 6.8 volts.... as soon as I turn the big disconnect switch ON.... the battery voltage drops and reads, 5.8 volts
This drop occurs, without me turning on the ignition switch..... when I start the engine and let it run for, 15-25 minutes at a high idle... I see that it charges the battery back up..... and the amp gauge goes back to Zero..... Is it normal for the battery to drop voltage when a main battery disconnect switch is turned on....??? IF not... what would likely be causing this drain....???

The battery should live" well over 8 months with out charging.
believe you have a battery problem or a draw. Remove the cables from the battery. Charge battery with a real plug in the wall charger and see what happens. t should hold the charge for months and months.

I agree that it seems like there is some type of “drain” or unknown load in your system. The voltage should not drop just because your turn the disconnect to on.

What voltage does the battery read when the disconnect is off and the solar charger is disconnected? If you are reading 6.8 volts with the charger connected you are reading the output voltage of the charger, not the battery voltage.

What does the ammeter do when you turn the disconnect on without the engine running? Does it show a discharge?

Another test is to remove the disconnect from the circuit. Does the battery voltage drop when you connect the negative cable to the battery?

How big are are your cables? The size should be marked on them.

If you disconnect the negative cable end from your battery and place your amp meter with one end on the negative battery terminal and the other end on on the cable you removed, you should see a reading on the meter if there is a draw.

Mike

I am inclined to agree with Rabaut's suggestion but be sure to use a amp meter capable of 30 amps as I think there is a heavy load and most common multimeters are only good for 10 amps then the smoke escapes.
Tony

Always a good idea to protect your equipment..... You could always put a small value fuse in line to see if it pops it....... but if a 6V battery is leaking 10 amp, that's 60 watts, that's going to be noticed without a meter.... I should think.... Prob best to keep a smoke net handy.....

Mike

I will do the checking and respond in the next few days... thanks all good suggestions... will check soon... Sunny

Hi... today... I disconnected the battery charger .. the battery reads 6.5V.... turned ON the big battery disconnect and it slowly dropped one tenth of a volt at a time, 6.4, 6.3, 6.2, 6.1, 6.0 & 5.9..... when I turned the disconnect switch ON, the amp meter showed discharge down to the 20 line...... when the switch is on .... the positive battery cable to the starter reads hot the same as the coil wire and on two of the terminals on the back of the ignition switch read hot ( with the ignition switch turn off).. The cut off switch is on the battery ground cable.... and both battery cables are New and the thick .002 correct size for 6 volt.....
There is defiantly a drain in the new wiring system... But.. where to start looking... the car starts and runs fine, and charges as it should.... any suggestions..???

You need to build a plan to check every circuit one at a time.

There are a couple of different approaches. Whichever way you go stay with that approach once you have started.

One approach is to start disconnecting wires and devices until the drain stops.

My recommendation is to go the opposite way. Disconnect everything and then start connecting until you see the drain.

I expect you have a dead short to ground somewhere. My best guess is the cutout in the charging circuit.

Here is what I found out today.... I disconnected wires to the ignition switch ...one at a time... It was still draining when I put the battery Disconnect switch on.... so I followed Rusty 37's advice and went to the charging system... disconnected the bat terminal on the voltage regulator... & turned on the bat switch... NO DROP in voltage, NO Drain...... so I hooked back up the Bat wire to the regulator and disconnected the Field connection... turn on the Bat switch and it Dropped again... so I disconnected the Armature wire on the regulator and turned on the Bat switch..NO DROP.... so I went to the Generator and disconnected the Armature wire on the Generator.... and there was NO DROP in Volts... hooked it back up to the arm post on the generator... and there was the Drop and Drain..... pulled off the generator and hooked the wire up to the arm post... turned on the disconnect switch... and there is a rapid drop of voltage.... some thing is shorting out inside the gen... the post is well insulated from the gen body... This 1102667 generator was/is charging.... but it is also shorting on the armature post..... I couldn't see any wires touching on the inside....
I am wondering if I can use my old #935B generator WITHOUT the cutout.. and wire the field & armature to the regulator instead.... ???? any ideas on this...?? there is not a generator repair shop within 300 miles from my home..... any body have a good #1102667 generator for sale...??

That is good progress! Here are some ideas.

Take the cover off of the regulator and see if any of the contact points are stuck closed. One of the 3 coils in the regulator is a cutout. If it is stuck closed it will drain the battery but let output from the generator go back to the battery.

Also check is there might be a short or ground within the regulator.

I'm not an expert on generators by part number. Are you trying to run a 3 brush generator with a 3 coil regulator? I'm not sure how that combination would work.

Rusty ... I checked the points in the regulator.. they all open freely and the regulator (3 coil) is new and very clean inside.... No, I am not running a 3 brush generator... I bought/installed a 2 brush (1941-1951
Chevy Delco Remy) Thus the 3 coil regulator.... I looked the regulator over real good, inside, today.. didn't see anything that might short.. but I will look again.... in a few days... looking now for a replacement generator Delco Remy #1102667 or 1102737......

4/20.... PROBLEM Found....
I had NOT Polarized the Generator... when I put it on the car.... so I touched the battery hot wire to the armature stud on the generator... an now there is no discharge or drop in the battery voltage when I TURN ON the battery disconnect switch... thank Rusty for the tip, about where to look.... Sunny

I have seen the instructions as to how and when to polarize the generator for decades, and have always followed that advice. This is the first time I have seen the result of not following that advice.

In 50 years of automobiles I dont remember ever polarizing a generator or having any problems as a result, bolt it on connect the wires send it out the door.
Tony

Well I have read, in several places that it is necessary to touch the armature post with the hot spark from the battery... why is it necessary..??
I do Not know why...
but I also opened the cover off of the regulator... and made sure all three points, in there opened and closed freely.... it could have been that the armature points were not opening before that...?? I do not have all the answers... but something changed... and now the battery stays up, with no drain on it.... That makes me happy.....

It is necessary to make sure that the current is flowing in the correct direction.

CONGRTULATIONS! These classic vehicles present their own challenges even though many people call them "simple".